Poor Turbo Selection - Need Help Brainstorming

[GTScotT]

Cheers Disco, I do appreciate the newer car vibe. For myself I actually have an S14 and am nearly finished with the setup. The sigma is sort of a side project for me, mainly my brothers with some help from myself. Realistically if I dont participate nothing will ever get done.

Looking under the bonnet and seeing the manifold etc really does make me sympathetic to the old astron lol, a lot of time and effort has gone into this setup and it would be a shame to give up on it. The money to date is also a major factor for me to try harder. I wont say how much has been spent to date, but it is a lot.

Just to be clear would LSA need to be a higher or smaller number? I will put my feelers out for a factory cam, brother wont like that but it may get us somewhere. Ill also try to track down a larger housing for the GT30.

[jet_r31]

higher=less overlap

not sure how mnay cams you've changed in sohc motors disco..but that reaks of problems

with turbo cam 10+yrs ago..things have changed a lot since then and cam makers have cottoned on what a

engine needs a lot better...we aren't getting old blower grinds anymore with large overlap that blow all the energy out the ass end. I think all the problems you mentioned come back to to lsa actually..

I've had people sell me blower grinds that where shocking 10+yrs ago when asking for turbo cams, and yes all those

problems existed, but the grinds these days are alot different.

Even a basic stage one cam with a 114lsa would outperform a "standard" cam in every way usually, theres more to cams

than just duration and lift, the way the cam is designed in regards to the lobe shape has a big effect on drivability,

Even going back to sohc cam rb30's, the tighe cams are quick lift cams, they run much more lift and duration than stock..but still make more bottom end and midrange torque than the stock cam and spool a turbo quicker...and make another 30-40rwkw..lol

twin cam stuff is a different kettle of fish again, and the designs are much more recent..

personally if i only had the choice of one , i'll take duration over lift any day of the week with a turbo car..providing i can change the LSA

cheers

darren

Edited December 29, 2012 by jet_r31

[DVS JEZ]

Jase has the car been tuned on both cams or only one? And if 1 which 1?

Maybe bring it up one day and i'll spend an hour on it too see if the ignition timing is tuned correctly by the last tuner

[GTScotT]

Cheers Jez ill probably take you up on that hour. Would be good to get a cost effective second opinion on the tune also. As stated I think its OK but then again im no tuner. Have you got software for an EMS stinger?

As for the cam it was originally tuned for the smaller cam and then was touched up with the larger. Not a great deal of time was spent on the larger but I dont think there was much left in it anyhow. An hour on your dyno will tell us A LOT though.

Darren im thinking ill force him back to the first cam which is a stage 2, has 230* @ .50 and 114* LSA. Do you think that cam is significantly better suited or think I am wasting my time?

I'll also see about getting a housing, maybe track down the supplier of the ones Scotty mentioned or see if Stao can make me one. Would you be more inclined to test a .82 or 1.06? My gut feel is saying go the 1.06

[DVS JEZ]

Yes i have the software but havent tuned one yet

[GTScotT]

First time for everything ;-)

[DVS JEZ]

All the same once i have a play

[wolverine]

I would give Jez a look before chasing your tail with new parts.

[jet_r31]

Id personally go back to the first cam for testing, as to me it takes one thing out of the equation, as in "theory" that one should

work fine with that setup. If you do fix the problem and its something else, then you can refit it later and re test it.

out of interest, what type of cooler is fitted?, much pressure drop?, and what valve springs? especially with big cam?

close to coil bind?, its not getting valve float from boost pressure?

The big one is something i would fit if a mate said i want a 2.6 turbo and i want to turn the world on its axis.

And even though i am no astron expert i'd spec that with a 116 LSA and a PT6466 with plenty of boost shoved up its ass.....lol

This is why i like old motors turboed and like working on them , yes they are a pain in the ass, but f**k me at least you have to

think and work some stuff out for yourself, much better satisfaction than buying most newer motors, any idiot can

get a good result out of a Rb25 etc..lol

cheers

darren

Edited December 30, 2012 by jet_r31

[Hanaldo]

any idiot can get a good result out of a Rb25 etc..lol

Oh

[jet_r31]

I woudn't take that to heart..lol, but look at how much more info there is out there for newer motors, its like building a oversized model kit

most of the time..cars being cars, its not always going to be smooth sailing for some unlucky ones..but thats just cars in general

thats why love and hate them at the same time!

cheers

darren

Edited December 30, 2012 by jet_r31

[Hanaldo]

Haha nah you're right mate, I can have a laugh at my expense

OT, I don't have anything useful to input, but I've been following the thread with interest. Keen to see how you go Scott!

[jet_r31]

I have to get of my ass and start doing my Rb25 soon..be funny after saying that if it makes no power....lol

cheers

darren

[GTScotT]

out of interest, what type of cooler is fitted?, much pressure drop?, and what valve springs? especially with big cam?

close to coil bind?, its not getting valve float from boost pressure?

The cooler is a china 450x300 (shorter variant to the generic 600x300). Was purch back in the day from JJ, quality seems fine and no issues. Cooler piping is 2.5" from outlet to throttle. Throttle is a little small but dont think that would hold it back that much. Not any smaller than an S14 VCT throttle body from memory.

Valve springs are actually the matching item for the cam. They were purchased as a set from camtech. Im gonna try get that smaller cam back in ASAP, need to beat bro to pulling the motor as hes wanting to rebuild the motor (not that it will help). Im wanting to find the problem and then retune on a fresh motor.

Cheers for the input guys, I'll find some time to pay Jez a visit soon and see what he and his dyno have to say. Hopefully a feeble issue can be found and sorted or at least the bigger issue will rear its ugly head.